1. Field of the Invention
The present invention relates to a ballast broom machine for sweeping ballast off a track, which comprises an elongated machine frame extending in a longitudinal direction and supported on the track by undercarriages for moving the machine frame in an operating direction, and a plurality of ballast brooms vertically adjustably mounted on the machine frame, the ballast brooms being spaced from each other in the longitudinal direction, each ballast broom comprising a rotary shaft extending perpendicularly to the longitudinal direction and flexible sweeping elements projecting radially from the rotary shaft.
2. Description of the Prior Art
A ballast broom machine of this type has been disclosed in U.S. Pat. No. 4,554,697, dated Nov. 26, 1985, in which one ballast broom is mounted immediately ahead of the front undercarriage and another ballast broom is mounted immediately behind the rear undercarriage. Each broom is provided with a leading deflector box arranged to move excess ballast from the center of the track to the shoulder. This machine is not capable of sweeping substantial amounts of ballast off the track.
Japanese utility model application disclosure No. 5001/81, published Jan. 17, 1981, discloses a small ballast broom machine comprising a machine frame supported on the track by two undercarriages wherebetween a ballast broom unit is vertically adjustably mounted. The ballast broom unit carries two brooms which may be used selectively or together. This machine, too, is not capable of removing substantial amounts of ballast from the track.
British patent No. 1,040,104, published Aug. 24, 1966, deals with a machine for the compaction of ballast in railroad track cribs. Three ballast brooms precede the ballast compactors in the operating direction, one of the brooms having a rotory shaft extending transversely to the longitudinal direction of the machine frame while the rotary shafts of the two other ballast brooms extend in the longitudinal direction. The two last-named brooms may be immersed in the ballast in the cribs to make it possible to sweep more ballast out of the cribs.
Finally, U.S. Pat. No. 5,097,608, dated Mar. 24, 1992, deals with a ballast regulator with a ballast plow and a vertically adjustable ballast broom at the rear end of the machine frame. This ballast broom has a rotary shaft extending transversely to the longitudinal direction in which the machine frame extends and a tranversely extending conveyor band precedes the ballast broom to remove swept-up excess ballast to the track shoulder. Two additional ballast brooms are arranged between the plowshares of the ballast plow to assist in the distribution of the plowed ballast between the track shoulders at an angle to the longitudinal direction.